iOS Development SwiftUI Framework 2

Question 1

What does `@ObservedObject` do in SwiftUI?

Accepted Answer

Subscribes a view to updates from an external ObservableObject

Answer

`@ObservedObject` watches an `ObservableObject` and re-renders the view whenever the object's `@Published` properties change.

Question 2

Which SwiftUI modifier adds padding around a view?

Accepted Answer

.padding()

Answer

The `.padding()` modifier adds insets around the view's content, with default or custom edge/size values.

Question 3

What is `@EnvironmentObject` used for in SwiftUI?

Accepted Answer

Sharing an ObservableObject across many views without explicit passing

Answer

`@EnvironmentObject` allows views deep in the hierarchy to access a shared model object injected higher up, without passing it explicitly.

Question 4

Which SwiftUI view displays a scrollable list from a collection?

Accepted Answer

List

Answer

`List` is SwiftUI's declarative component for displaying a scrollable, structured list of rows from a collection.

Question 5

What does the `.onAppear` modifier do in SwiftUI?

Accepted Answer

Runs a closure when the view appears on screen

Answer

`.onAppear` attaches a side-effect closure that runs each time the view becomes visible on screen.

iOS Development Practice Test